What is the rational foundation for the doctrine of universal human rights? Some philosophers, such as Alan Gewirth, argue that it may be discovered simply by reflection on certain essential features of the human constitution.  However this approach has significant problems, achieving its ends by smuggling certain tacit premises into the argument. A better approach is one that appeals to the communal practices and traditions within which doctrines of human rights have evolved historically.  It is here that Alasdair MacIntyre's work becomes relevant, because it maintains that traditions have a rationality of their own, and that all rationality is in some sense traditional. That MacIntyre himself has used these ideas to dismiss the doctrine of universal human rights only shows the extent to which MacIntyre (like many others) has misunderstood the true character of that doctrine.